At this weeks production of Carousel we are using two low level foggers as opposed to dry ice machines. I am currently having a "debate" with the crew concerning the merits of each. I have no problem obtaining free dry ice so that is not an issue.
I also acknowledge the danger of using what is really nothing more than a big kettle and handling/storing stuff which will take the skin off an inexperienced user compard to a nice self contained box.................BUT
I think the effect of dry ice is far better than a low level fogger. It does what it does better and having done it, doesnt hang around and it doesn't fill the pit and upset the delicate musicians.
I admit some hired machines are disallowed word and leak but I am talking about the visual effect.
What do you think??

Over the years I've used both and have come down firmly of the side of dry ice.

For those not familiar with dry ice substitues, they're basically a smoke machine that used long persistance smoke. the smoke is passed accross a big chiller to get the smoke to stay low.

As I said before I've tried a number of low foggers and all have been a huge let down and not worth the hire cost (normally more than dry ice) They work well on a cold stage - but once you've got some lights up the fog disspates within a couple of feet from the machine.

The only machine that has come anywhere near to my expectations was a Jem machine - unfortunatly it was noisy and almost 5' x 5' x 4' not easily concealed!!

Although dry ice has issues wen handling etc, it at least is inert thus allowing lights to place in the flow giving great effects - since synthetic smoke is water based there is always the possibility of and electrical problem!

Having spoken to a friend at Le Maitre (who manufacture low foggers) they also concure that even after 10 years this technology is far from matching dry ice.

So for me dry ice currently wins hands down.


As an aside things are going to get more difficult for synthetic smoke machines/hazers and foggers since their is currently some debate running over the safe exposure levels of this equipment especially in the states. Ths machines were sold as harmless - and certainly don't irritate (people coughing when they see smoke is more a psychological reaction), certainly oil based crackers (hazers) will get the chop soon I have no doubt - (if you use one of these they give great effects but leaves and oily residue over the whole rig - what are they doing to your lungs?)

I agree with Martin but check the machine on delivery they are very suscetible to misuse and damage. Try to get one picnic cooler to fit in a larger one for better storage.

Robin

Just done a show where it was insisted we used log fog/ dry ice

on a cost bases we used low fog, and it worked quite well - in fact beter than I hoped.

To get the effect we used 2 Antari low foggers - thses use frozen ice pack as the chiller and so are quiet ( no hissing from smoke)

They have a fog time of about 30secs at max output before they reheat (the smoke generator) so I set the ouputs so that one was reheating whilst the other was discharging fog. (they have a continious button so I switched one on and as it finished switched the second one on - in this way I had a constant fog.

Cost for two machines and 2.5 litres of fluid each (more than enough for 3 fog effects per night for 7 performances) ?120 total - much cheaper than dry ice.

Typically for fog it doesn't drift that far and unlike smoke it doesn't exit the machine at high velocity which keeps the effect local. the dancers did waft it about nicely.

THe effect worked well and didn't cost that much - you are never going to get a top of the pops/ Phantom of the Opera effect without serious equipment/money, but I was happy enough to use them again and recommend them

On a certain show that I was associated with for a year (I don't want to fall foul of copyright etc) we used 2 Gem Heavy Fogs and 3 Howie tubs with a 10kg bag of dry ice in each. This produced a waist high carpet for the length of a three minute song on a very large stage and the 1-in-12 rake meant that it rolled down beautifully. BUT this was definitely in the realms of the professional level of cost and unless your initials are DH (as in DHA), don't bother.

Dave

Here is an article copied from ABTT. I am not sure how long ago the project that Dave talks about was, but would be interested in his comments in today's environment. Does he think the same thing could have been done today? Still the post is worth putting here for all to refer to. I have the Peasouper and would love to use it again, but also have the Antari low fogger which is great. In fact thinking of a second one.

Dry Ice

When a Dry Ice Machine was operated on stage during a preview performance of a popular musical - carbon dioxide (CO2), being heavier than air, seeped into the pit. A member of the theatre staff who was in the orchestra pit became disorientated and collapsed. The member of staff was taken to hospital and later released, fortunately without suffering any apparent long-term injury.

HSE prosecuted the producer on two counts:

1. Under COSHH exposing a person to Carbon Dioxide fumes.

11. Health and Safety at Work, Failure to asses the risk.

Fines were imposed amounting to ?4000,

The use of Dry Ice comes under the COSHH regulations which came into force on 1st October 1989, applying to all work activities where hazardous substances are used. COSHH Regulations (now forming part of the Health and Safety at Work Regulations) involve all employees, HOD's and Theatre Managers in an assessment to prevent a health risk that may arise from a substance 'Hazardous to Health'.

These machines are used extensively in Pop Concerts, Ballet and Pantomime. This accident highlights the problems associated with such effects and the need for technicians to be aware of the associated problems.

Solid carbon dioxide is immersed into hot water and the resulting vapour is usually directed by a fan and ducting across the stage. Often the dry ice is purchased in pellet form or solid blocks and when broken up into smaller pieces allows a more rapid vaporisation which increases the dry ice effect.
The effect produces a solid white cloud mist over the stage. Carbon dioxide does not support life. CO2 is heavier than air and can exclude the oxygen in the air by flowing into low-lying confined spaces; anyone breathing in these conditions for only a short time, will at best become drowsy and at worst is liable to suffocation.

A number of points need to be observed:

1. It is important that everyone on stage should be aware of the dangers of CO2 and know when the dry ice machine is to be operated. Operation of the machine should take into account safety of the staff, performers and audience. Vapour outlets should be in sight of the operator at all times.

2. Rehearsal of the effect must be carried out to determine the direction of flow of the dry ice vapour and people coming into contact with it. Precautions must be observed if dry ice vapour falls into the orchestra pit or flows into areas such as basements, under stage storage or the auditorium. Care needs to be taken to move the machine to a new location or redirect ducting. The amount of Dry Ice should be limited to the minimum necessary to create the desired effect.

3. Good ventilation is important - as the vapour becomes invisible the gas concentration may become difficult to determine. Health and Safety recommend that if there is any 'doubt about the concentration present, expert advice should be sought to monitor the oxygen and carbon dioxide levels before the equipment is used'.1

Yes, the setup was reviewed regularly. The main concern, obviously, was the orchestra, especially those who have to suck and blow for a living. At each stage all concerned were asked for opinions and all concerns were addressed. One thing that seemed to help greatly was the fact that the pit was fully enclosed and the house air-con/recirc system was able to maintain a positive air pressure coming from the pit. As far as I am aware, this was still the practice upto about 4 years ago when the show came off.

Looking at specific points:

1) The operator had no view of the stage at the time of release, this was simply directed by SMs.
2) It was very well rehearsed - the show had been running for 10+ years when it closed.
3) Ventilation, at the end of the number, cast leaving the stage rapidly cleared any remaining vapours. The pit was cleared by opening a door, thus removing the positive air pressure and venting everything out through the low door.

I take the point that everything is getting tighter with respect to H&S, but I think that part of the point is that more and more is being asked of the technical side of theatre and that we, as amateurs are being asked to keep up with the Pro's. The time and money that the big boys enjoy is not available to us. This means that corners get cut. In my mind this means that we not only have to keep H&S standard up with the Pro's, but arguably we should be striving to exceed them. Having seen both side of the story, this should not be too difficult.

Nick, is there an equivalent article about the use of Smoke/Haze?

Regards,

Dave

I don't know if it's me but..

Low fog tastes really oily - I can handle smoke and haze in a confined area - but the low fog is weird. also when you dissappear in a cloud of it you really can't see through it - unlike smoke (within reason) I guess it's the density - but the oily taste is worriyng

I am not sure about the low smoke being more oily. In fact I ran out of the correct smoke so used normal smoke fluid. It smelt the same. I have had a look Dave and cannot find anything about smoke machines or hazers. I have found a site which explains smoke machines some more.

http://www.concept-smoke.co.uk/about.htm